Intercom Door Strike Not Unlocking
Troubleshoot an intercom system where the door station or monitor works but the electric strike does not release.
Most common causes in practice
| Possible cause | What it looks like | First check |
|---|---|---|
| Wrong relay terminal | Click or event appears, but no unlock | N/O vs N/C wiring |
| Lock PSU issue | No release power at the strike | Measure PSU output and load path |
| Strike alignment / door hardware | Works sometimes or only when door is pushed/pulled | Mechanical alignment |
| Wrong strike type | Behaviour does not match expectation | Fail-safe vs fail-secure assumption |
How to get the most value from this page
- Use this page with the relevant calculator, template, planning pack or quote brief.
- Save or print any generated output before changing inputs.
- Check all assumptions against actual device manuals and the real site layout.
- Update the as-built documentation after installation or troubleshooting.
High-traffic intercom fault page
Door release faults are often caused by relay logic, lock PSU, N/O vs N/C wiring or strike alignment.
Use with a template
Open templates to document cables, devices and handover details.
Use with a calculator
Open calculators to check PoE, storage, ports or voltage drop.
Create a quote brief
Open quote briefs to generate a structured request.
Step-by-step diagnosis
Check whether the fault is constant or intermittent and whether it affects one device or the whole system.
Verify power, polarity, PoE, battery, terminations and patching.
Confirm IP address, zone, reader address, relay mapping, app registration or recording settings as relevant.
Use the related diagram to confirm the device is wired to the correct input, output or network path.
Quick checks
- Check if the intercom relay is dry contact or powered output.
- Verify the separate lock PSU voltage and current capacity.
- Confirm N/O or N/C relay wiring and unlock timing.
- Test the strike directly with suitable power if safe to do so.
Related diagrams and hubs
Relevant product categories
If the fault points to failed or unsuitable hardware, SecurityWholesalers is a useful reference for relevant security products and accessories.
Quick FAQs
Can I copy this diagram exactly?
Use it as a planning reference, then confirm terminal names, power requirements and cabling against the actual product manuals.
What should I document?
Document cable IDs, device names, power supplies, switch ports, input/output numbers and final commissioning results.
Quick FAQs
Can I use this as a final design?
No. Use it as a planning and documentation resource, then confirm the final design against product manuals and site requirements.
What should I do next?
Use the related calculator, template, planning pack or quote brief so the information becomes useful project documentation.